Numerous different types of reel-type gaming machines have been developed to provide desirable game features and play characteristics in these types of wagering games. As used in this disclosure and the accompanying claims, a reel-type gaming machine comprises a gaming machine in which at least some results are displayed to the player in the form of an array of game symbols, where each game symbol is displayed on the periphery of a spinnable reel, either a physical reel or a video simulation of such a reel. For example, a reel-type gaming machine may include a display system with five adjacent reels (either physical reels or video simulations) all aligned along a horizontal axis of rotation, with each reel showing a line of three or more game symbols in the array of symbols. Other reel-type gaming machines may show only a single symbol on each physical or simulated reel and include a separate physical or simulated reel for each symbol location in the array of game symbols used to display results. In all of these reel-type gaming machines, winning results are shown at least partially by the particular pattern or patterns of game symbols appearing in the array of game symbols for a given play of the game.
One feature that has been applied in reel-type gaming machines can generally be referred to as a respin feature. For example, U.S. Pat. No. 5,704,835 shows a respin feature in which a player may select one or more reels to respin in order to generate new game symbols for the array. Another type of respin game awards some number of free spins and allows the player to play their free spins in an effort to win additional prizes. U.S. Pat. No. 7,121,942 shows an example of a free spin game. Yet other types of reel-type gaming machines include a “nudge” feature in which the reels initially come to rest for a play of the game, and then one or more of the reels “nudge,” that is, move to the next stop position to make the final array of game symbols for the play of the game. U.S. Patent Application Publication No. 2004/0048650 shows such a nudge feature. Although all of these types of game features may provide improvement over the basic reel-type game play, there remains a need to provide new game features which can capture and maintain the player's interest and provide a more satisfying gaming experience.